Impact of tourism on groundwater extraction on the island of

Impact of tourism on groundwater extraction
on the island of Langeoog, Germany
Georg Houben
Federal Institute for Geosciences and Natural Resources(BGR),
Hannover, Germany
[email protected]
Water supply on the East Frisian Islands
The East Frisian Islands are a chain of barrier islands in
the Wadden Sea area of the North Sea. Extensive intertidal mudflats separate them from the coast.
Baltic Sea
North Sea
N o r t h
Hannover
D
s t
a
E
CZ
0
200km
Juist
N
s
I s l a n d Wangerooge
n
s i a
i
r
F
Spiekeroog
Langeoog
Norderney
CH
S e a
PL
Niedersachsen
NL
F
The island of Langeoog has three freshwater lenses.
The separation was caused by storm flood inundations
in historical times, especially during the 17th century.
Baltrum
Mellum
n
d d e
a
W
S e a
Ja
Borkum
SW
de
Rainwater infiltrating into the dunes forms freshwater lenses in dynamic equilibrium with surrounding saline water. Water supply on most islands depends on these lenses.
Example Langeog
Memmert
Wittmund
Leybucht
elg
Kaap dunes
[Water work West]
(m)
20
Jever
ndz
W
E
Wilhelmshaven
Norden
Ra
NE W
Melkhörn dunes
Heerenhus dunes
[Water work East]
Kleine
Große Schlopp
Schlopp
Eastern dunes
(m)
20
Meierei
sea level
sea level
at
Aurich
-30
-30
Jadebusen
0
water well
fresh water
25 km
12.5
0
1 km
saline water
Groundwater extraction
Borkum
Juist
Norderney
Langeoog
Spiekeroog
Cross-section of the East Frisian coast (modified after Streif 1990)
The economic base of the islands is tourism. The high
seasonality of this business and the elevated water demand of tourists stress the limited water resources. Climate change might exacerbate this situation.
[m³/a]
Cross-section of the freshwater lenses of Langeoog
(modified after Streif 1990).
800,000
300,000
940,000
334,000
140,000
Water supply solely depends on groundwater pumped
from the western freshwater lens. To prevent upconing
of underlying saline water, extraction is distributed over
20 shallow wells (10 to 18 m depth) which pump
intermittently at low rates of around 10 m³/h.
The islands Baltrum and Wangerooge are
supplied from the mainland via pipeline
Water demand
Historical development
Seasonal variations
groundwater consumption
groundwater extraction
overnight stays
450
groundwater volume [m³/a x 1000]
3
400
3000
2800
2600
2400
2200
2000
1800
1600
1400
1200
1000
800
600
400
200
350
300
250
2
200
150
1
1 = post-war refugees
2 = water work East activated
3 = water work West shut down
100
50
0
1940
1950
1960
1970
1980
1990
2000
2010
The 2011 extraction of 334,000 m³/a is about a quarter
less than the peak extraction of 452,000 m³/a recorded
1983, although the number of overnight stays has
remained more or less stable at least since 1990!
Water demand varies strongly according to seasons, vacation periods, public holidays and individual weekends. The lowest water demand on
Langeoog during the off-season of 2011 was 238
m³/d while the maximum during the Easter holidays
reached 1,894 m³/d, a factor of eight between maximum and minimum!
180
1500
160
140
1400
120
100
1300
15
14
13
12
11
10
9
8
7
1990
1995
2000
2005
2010
Guest numbers rise but the number of overnight stays remains constant = shorter vacations
= more frequent cleaning of rooms and washing of towels and linen
(5)
(6)
(1)
400
(?)
(?)
(7)
(2)
(1)
200
0
(3)
2000
1600
1200
Langeoog
(4)(5)
Qtot= 333,808 m³/a
(6)
(7)
(1)
(1)
800
0
Groundwater extraction on the islands of Spiekeroog and Langeoog
in the year 2011 showing strong seasonal demand variation. Peaks
11 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 2012
0
2
1. .02. .03. .04. .05. .06. .07. .08. .09. .10. .11. .12. .01.
are even more pronounced on the smaller island of Spiekeroog.
0
.
01
01
01
01
01
01
01
01
01
01
01
01
01
After data by OOWV.
Average monthly air temperature [°C]
1600
1,000 overnight stays per year
1,000 guests per year
average overnight stays
per guest
guests
overnight stays
Qtot= 150,618 m³/a (3)(?)
(4) = Ascencion
(5) = Pentecost
(6) = Unification Day
(7) = Autumn break
400
Conclusions
air temperature
moving average (48 months)
moving average (96 months)
25
1700
Spiekeroog
600
Climate change
220
200
800
At 125 liter per day and person, the 2,000 permanent residents consume about 92,000 m³/a.
Subtracting this from 2011´s consumption, the remaining 242,000 m³/a, equivalent to about 72 % of
all extraction, must be attributed to tourism.
Tourism
Langeoog 2011:
(a) 2,000 permanent residents
(b) 150 seasonal workers
(c) 1,540,000 overnight stays
(d) 124,000 day visitors
(1) = X-mas/New Year
(2) = Carnival
(3) = Easter
(4)
1000
Groundwater extraction [m³/d]
500
overnight stays per year [x 1000]
Consumption steadily rose until the 1980s, parallel to
increasing tourism. With the implementation of watersaving household appliances in the 1990s, consumption
significantly decreased.
25
20
20
15
15
10
10
5
5
0
0
-5
-5
u
u
u
u
u
-10
00
19
-10
10
19
20
19
30
19
40
19
50
19
60
19
70
19
80
19
90
19
00
20
10
20
Air temperature records from the island of Norderney
indicate an increase of the average annual
temperature of about 2.0° C over the last 115 years.
Especially summers in the last 20 years have become
warmer and cold winters have become less frequent.
Will this cause an increase in water demand?
u
Water supply on East Frisian Islands mainly depends on freshwater lenses
Tourisms accounts for more than 70% of all water
consumption
Strong demand variations over the course of the
year due to tourist seasons
Water consumption has decreased due to implementation of water saving installations although
number of overnight stays has become constant
Tendency towards more frequent but shorter vacations might increase demand again (more frequent
washing and cleaning)
Future effects of climate change (rising temperatures in summer) might be a game-changer.
The results presented on this poster were elaborated in the framework of the BGR project FLIN
(Freshwater Lens Investigations)
References:
Streif, H. 1990. Das ostfriesische Küstengebiet: Nordsee, Inseln, Watten und Marschen. Sammlung
geologischer Führer 57, 376 p., Berlin.
Acknowledgement:
We thank the Oldenburgisch-Ostfriesischer Wasservernband (OOWV) for data on water consumption